This invention relates to a light emitting diode (LED) display device and it relates, more particularly, to such an arrangement wherein several segments are illuminated to display information.
In light emitting diode displays, typically known also as LED displays, a key problem is to distribute the light emitted by a very small semiconductor chip, having a rather small emitting region with typical length of, for example, 300 .mu.m or less, over a large luminous segment, whose dimensions (length/width) are, for instance, 1 mm.times.5 mm.
Conventional displays include, for example, the so-called seven-segment displays. In these devices the numerals or symbols are composed of individual luminous bars (luminous segments). With a total of seven segments the numerals 0 to 9 can be represented, and for special cases a limited number of letters. The basic pattern is an upright rectangle, divided in the middle by a horizontal bar. The individual luminous segments are illuminated for display with light emittng diodes, abbreviated LED. These systems are widely used because they offer the advantages of low power consumption, small space requirement, great brightness and good readability also under small angles of incidence.
In these current seven-segment displays, a funnel-shaped reflector, at the base of which the LED chip is located, is used in a cap for each luminous segment. This funnel-shaped reflector, which functions on the principle of diffuse reflection, is filled with a resin containing a little diffusor substance and is connected to the chip-carrying lead frame (metal spider).